Lactam-based pigments and the use thereof in the production of coloured plastics or polymeric colour particles

ABSTRACT

The present invention relates to novel pigments of formula 
                 
 
(1), wherein R 1  is hydrogen or C 1 -C 12 alkyl, R 2  is hydrogen, —CN, —COO-aryl, —COO-heteroaryl, —CONH-aryl or —CONH-heteroaryl, and R 3  is the radical of a heteroaromatic compound of formula  
                 
 
or R 2  and R 3  together form a radical of formula  
                 
 
wherein R 4 , R 5 , R 6  and R 7  are defined herein and to a process for the preparation of those pigments, and to their use in the production of coloured plastics or polymeric colour particles.

The present invention relates to novel lactam-based pigments, to aprocess for the preparation of those pigments, and to their use in theproduction of coloured plastics or polymeric colour particles.

Methods for colouring synthetic materials, such as plastics andpolymeric colour particles, in the mass, using pigments, are known. Ithas been found, however, that the pigments used in such a method do notalways fully meet the highest demands, especially with respect tofastness to light, thermal stability and/or tinctorial strength; nor dothey completely cover the entire palette of shades desired. There isaccordingly a need for new pigments that yield light-fast, thermallystable and tinctorially strong colorations, especially in the yellow tored colour range, and that exhibit good general fastness properties.

It has now been found, surprisingly, that the pigments according to theinvention substantially meet the above criteria.

The present invention accordingly relates to pigments of formula

wherein

-   -   R₁ is hydrogen or C₁-C₁₂alkyl,    -   R₂ is hydrogen, —CN, —COO-aryl, —COO-heteroaryl, —CONH-aryl or        —CONH-heteroaryl, and    -   R₃ is the radical of a heteroaromatic compound of formula    -    or    -   R₂ and R₃ together form a radical of formula        wherein    -   R₄ and R₅ are each independently of the other —CN, —COO-aryl,        —COO-heteroaryl, —CONH-aryl or —CONH-heteroaryl,    -   R₆ is a radical of formula    -   R₇ is halogen, and    -   R₈ and R₉ are each independently of the other C₁-C₄alkyl.

R₁ as C₁-C₁₂alkyl is, for example, methyl, ethyl, propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl,nonyl, decyl, undecyl or dodecyl.

Aryl in —COO-aryl and —CONH-aryl in R₂, R₄ and R₅ is each independentlyof any other, for example, phenyl which is unsubstituted or substitutedby methyl or by halogen, especially by chlorine.

Heteroaryl in —CONH-heteroaryl and —COO-heteroaryl in R₂, R₄ and R₅ iseach independently of any other, for example, pyrrole, furan, thiophene,pyridine, imidazole, thiazole, piperazine or pyrimidine.

Preferably, R₁ is hydrogen or C₁-C₆alkyl. Special preference is given toR₁ being hydrogen.

Preferably, R₂ is hydrogen or —CN. Special preference is given to R₂being hydrogen.

Preferably, R₄ is hydrogen or —CN. Special preference is given to R₄being hydrogen.

Preferably, R₅ is hydrogen or —CN. Special preference is given to R₅being hydrogen.

R₇ is preferably chlorine.

R₈ and R₉ as C₁-C₄alkyl are each independently of the other methyl,ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl or, especially,tert-butyl.

The present invention relates also to the preparation of pigments offormula (1).

Preparation of pigments of formula (1) according to the invention iscarried out, for example, by reacting a compound of formula

with a compound of formula

whereinX is ═NH or ═O, to form a compound of formula

and optionally, when X is ═NH, further reacting the compound of formula(52) with an active-methylene compound, for example of formulaR₄-CH₂-R₅.

The present invention relates also to a method of producing colouredplastics or polymeric colour particles, which comprises mixing a highmolecular weight organic material and a tinctorially effective amount ofat least one pigment of formula (1) with one another. The colouring ofhigh molecular weight organic substances with the pigment of formula (1)is carried out, for example, by admixing such a pigment with thesubstrates using roll mills or mixing or grinding apparatuses, as aresult of which the pigment is dissolved or finely dispersed in the highmolecular weight material. The high molecular weight organic materialtogether with the admixed pigment is then processed using methods knownper se such as, for example, calendering, compression moulding,extrusion, coating, spinning, pouring or injection moulding, as a resultof which the coloured material obtains its final form. Admixture of thepigment can also be effected immediately prior to the actual processingstep, for example by continuously and simultaneously feeding a solidpigment, for example in powder form, and a granulated or pulverulent,high molecular weight organic material and, optionally, also additionalingredients, such as, for example, additives, directly into the intakezone of an extruder wherein mixing occurs just before processing.Generally, however, it is preferable to mix the pigment Into the highmolecular weight organic material beforehand, since more uniformlycoloured products can be obtained.

In order to produce non-rigid shaped articles or to reduce theirbrittleness, it is frequently desirable to add so-called plasticisers tothe high molecular weight compounds prior to shaping. There may be usedas plasticisers, for example, esters of phosphoric acid, phthalic acidor sebacic acid. In the method according to the invention, theplasticisers can be incorporated into the polymers before or afterincorporation of the colorant. It is furthermore possible, in order toachieve different colour shades, also to add to the high molecularweight organic substances, in addition to the pigment of formula (1),further pigments or other colorants in any amounts, optionally togetherwith further additives such as, for example, fillers or siccatives.

Preference is given to the colouring of thermoplastic plastics,especially in the form of fibres. Preferred high molecular weightorganic materials that can be coloured in accordance with the inventionare very generally polymers having a dielectric constant ≧2.5,especially polyester, polycarbonate (PC), polystyrene (PS), polymethylmethacrylate (PMMA), polyamide, polyethylene, polypropylene,styrene/acrylonitrile (SAN) and acrylonitrile/butadiene/styrene (ABS).Especially preferred are polyester and polyamide. More especiallypreferred are linear aromatic polyesters, which can be obtained bypolycondensation of terephthalic acid and glycols, especially ethyleneglycol, or condensation products of terephthalic acid and1,4-bis(hydroxymethyl)cyclohexane, such as, for example, polyethyleneterephthalate (PET) or polybutylene terephthalate (PBTP), and alsopolycarbonates, for example those obtained fromα,α-dimethyl-4,4-dihydroxy-diphenylmethane and phosgene, or polymersbased on polyvinyl chloride and on polyamide such as, for example,polyamide 6 or polyamide 6.6.

The pigments according to the invention impart tinctorially strongshades to the above-mentioned materials, especially the polyester andpolyamide materials, with very good in-use fastness properties, theseespecially being good light-fastness and good thermal stability.

The Examples that follow serve to illustrate the invention. Unlessotherwise specified, parts therein are parts by weight and percentagesare percentages by weight. The temperatures are given in degreesCelsius. The relationship between parts by weight and parts by volume isthe same as that between grams and cubic centimetres.

EXAMPLE 1

10.2 parts of 2-indolinone are heated to 90° together with 14.3 parts of3-iminoisoindolinone hydrochloride and 7.7 parts of potassium acetate in100 parts of dioxane and 20 parts of glacial acetic acid and stirred at90° for a further 4 hours. The reaction product that precipitates out isfiltered off with suction and is washed with a 5:1 mixture of dioxaneand glacial acetic acid and then water. After drying, 14.1 parts of thepigment of formula

are obtained, which colours polyester in the mass in yellow shades, withvery good thermal stability and light-fastness.

EXAMPLE 2

4.4 parts of 2-cyanobenzamide are heated to 175° together with 4.1 partsof 2-indolinone in 25 parts of o-dichlorobenzene and stirred at thattemperature for a further 6 hours. After cooling, 4.4 parts of thepigment of formula (100) precipitate out.

EXAMPLE 3

13.3 parts of 2-indolinone are dissolved in 300 parts ofN,N-dimethylacetamide at room temperature and the resulting solution isadded to a solution of 14.5 parts of diiminoisoindoline in 150 parts ofN,N-dimethylacetamide at room temperature. On being left to stand for 48hours and dilution with water, 25 parts of the pigment of formula

precipitate out.

1 part of the resulting product is stirred under reflux in 50 parts of85% acetic acid for 4 hours. After cooling, filtration and drying, 0.5part of the pigment of formula (100) is isolated.

EXAMPLE 4

2.6 parts of the pigment of formula (101) prepared in Example 3 arestirred in a mixture of 70 parts of 98% acetic acid and 10 parts ofdimethylacetamide. After addition of 2 parts of dimedone, the reactionmixture is heated to 80° and is stirred at that temperature for afurther 12 hours. After dilution with methanol, 2.7 parts of the pigmentof formula

precipitate out, which colours polyester in the mass in red shades.

EXAMPLES 5-11

By replacing the 2.7 parts of dimedone in Example 4 with an equivalentamount of the active-methylene compound indicated in column 2 of Table 1and proceeding as indicated in Example 4, pigments having the shadesindicated in column 4 are likewise obtained. TABLE 1 active-methyleneEx. compound pigment of formula shade 5

red 6

red 7

dark-red 8

claret 9

claret 10

scarlet 11

scarlet

EXAMPLES 12-21

By replacing the 14.3 parts of 3-iminoisoindolinone in Example 1 with anequivalent amount of the carbonyl or aldehyde compound indicated incolumn 2 of Table 2 and proceeding as indicated in Example 1, pigmentshaving the shades indicated in column 4 are likewise obtained. TABLE 2carbonyl/aldehyde Ex. compound pigment shade 12

yellow 13

yellow 14

orange 15

yellow 16

yellow 17

yellow 18

yellow 19

yellow 20

yellow 21

yellow

EXAMPLE 22

5.2 parts of the pigment of formula (102) from Example 4 and 1 part of 1,4-phenylene-diamine are stirred under reflux in a mixture of 500 partsof ethanol and 50 parts of acetic acid for 24 hours. The precipitate isfiltered off with suction and purified using a 1:1 mixture ofdimethylformamide and acetone. 3.8 parts of the pigment of formula:

are obtained, which colours polyester in the mass in dark-red shades.

Colouring Example

1200 parts of polyester granules (PET Arnite D04-300, DSM) are dried at130° C. for 4 hours and then mixed with 0.24 part of the pigment offormula

in a “roller rack” mixing apparatus at 60 revolutions per minute for 15minutes, until homogeneous.

The homogeneous mixture is extruded in an extruder (twin screw 25 mm,from the company Collin, D-85560 Ebersberg) having 6 heating zones, at amaximum temperature of 275° C., cooled with water, granulated in agranulator (Turb Etuve TE 25 from the company MAPAG AG, CH-3001 Bern)and then dried at 130° for 4 hours, resulting in yellow-colouredpolyester granules having good all-round fastness properties, especiallyhaving very good light and high-temperature-light fastness properties.

1. A pigment of formula

wherein R₁ is hydrogen or C₁-C₁₂alkyl, R₂ is hydrogen, —CN, —COO-aryl,—COO-heteroaryl, —CONH-aryl or —CONH-heteroaryl, and R₃ is the radicalof a heteroaromatic compound of formula

 or R₂ and R₃ together form a radical of formula

wherein R₄ and R₅ are each independently of the other —CN, —COO-aryl,—COO-heteroaryl, —CONH-aryl or —CONH-heteroaryl, R₆ is a radical offormula

R₇ is halogen, and R₈ and R₉ are each independently of the otherC₁-C₄alkyl.
 2. A pigment according to claim 1, of formula


3. A process for the preparation of a pigment of formula (1) accordingto claim 1, which comprises reacting a compound of formula

with a compound of formula

wherein X is ═NH or ═O, to form a compound of formula

 and optionally, when X is ═NH, further reacting the compound of formula(52) with an active-methylene compound.
 4. A method of producingcoloured plastics or polymeric colour particles, which comprises mixinga high molecular weight organic material and a tinctorially effectiveamount of at least one pigment of formula (1) according to claim 1 withone another.
 5. A method of producing coloured plastics or polymericcolour particles, which comprises mixing a high molecular weight organicmaterial and a tinctorially effective amount of at least one pigment offormulae (100) to (120) according to claim 2 with one another. 6.(cancelled).
 7. Plastics or polymeric particles coloured with a pigmentof formula (1) according to claim 1.